This invention provides a means and apparatus for coupling tubular members of the type used in piling for offshore platforms. It particularly relates to the use of a flexible or non-rigid stabbing means assembly to provide increased alignment tolerances and to assist in correcting minor misalignments. The stabbing means can be left in place, as a plug, or removed as desired.
The need for some form of a flexible stabbing means for aligning and joining successive sections of tubular members used in piling and the like is needed, especially where lateral movement of the members is difficult to control.
U.S. Pat. No. 1,025,759 teaches a resilient, malleable metal sleeve which is attached with bolts in the end of one tubular member. When the projecting end of the sleeve is forced into a companion tubular member, "spring-like" projections from the sleeve cause the sleeve to tightly "hug" the other pipe to facilitate alignment of the members.
U.S. Pat. No. 1,225,855 teaches the use of a cast steel or malleable iron bushing to align contiguous segments of steel and concrete piles. The bushing is shaped to snugly fit within the interior of the piles. A flange upon the bushing bisects the bushing and separates the two abutting piles.
U.S. Pat. No. 2,963,090 teaches a rigid aligning means to permit the mounting of a blowout preventor on top of a well casing.
These early devices have not satisfied the need for better alignment and coupling devices. This is illustrated by U.S. Pat. No. 3,485,051 which teaches a complex funnel shaped device and probe assembly with a double tapered guidance apparatus.
The need for rupturable piling guides is demonstrated in U.S. Pat. No. 3,533,241 which teaches a rupturable seal assembly for closing the lower ends of tubular members. This facilitates the floating of platforms to points of installation and prevents the entry of silt and other debris when the tubular members are placed on the bottom prior to the driving of pilings or the drilling of wells. A rubber diaphragm is used as the rupturable seal member.
U.S. Pat. No. 3,577,737 teaches the use of a device which compresses a rubber plug, when desired, to effect a seal within a tubular member.
Another mechanical plug is taught in U.S. Pat. No. 3,613,381 wherein the closure member is in the form of a truncated cone welded at its periphery to the inner wall of the tubular member. The cone is equipped with a tearing arm which, when pulled, tears the conical plug from the inner surface of the tubular member.
The continuing existence of the problem of tubular alignment is further exemplified by U.S. Pat. No. 3,859,806 wherein a drogue and probe are affixed to the legs of jackets or substructure components of an offshore platform. The drogue has longitudinal slots into which latches on the surface of the probe fit.
U.S. Pat. No. 4,142,371 teaches a removable closure apparatus for hollow tubular members. A cable is coiled within the annulus of a moldable material that acts as the seal between the interior of the tubular member and the apparatus. The seal is broken when the cable is torn from the moldable material, permitting removal of the closure.
The recited art shows the need for a flexible stabbing means which can be a plug, part of a drogue and probe assembly, can latch into a mating part on another tubular member and which can be removed with relative ease. This invention provides the means for accomplishing all of these results simply and inexpensively.